Submarine snorkel camouflage method

ABSTRACT

1. In combination with a submarine having a hull, a snorkel housing extending vertically from said hull, a water nozzle having a horizontal flow axis fixedly secured to said snorkel, means connected to said nozzle for admitting water thereto, and adjusting means for controlling the amount of water and shape of water spray released from said nozzle, whereby the amount of radar echo from said exposed submarine is effectively diminished and detection of said submarine is obviated.

United States Patent Hymowitz [54] SUBMARINE SNORKEL CAMOUFLAGE METHOD [72] Inventor: Emil W. l-lymowitz Silver Spring,

[73] Assignee: The United States of America as represented by the Secretary of the Navy [22] Filed: Dec. 16, 1958 [21] Appl. No.: 780,904

[52] US. Cl ..ll4/15 [51] Int. Cl. .3633 9/00, 863g 9/02, B63g 13/00 [58] Field oiSearch..114/15,l6,16.1,16.11, 240 A", 343/18,18.1,18.2,15, 700, 709, 710, 719,

[56] References Cited UNITED STATES PATENTS 1,222,156 4/1917 Steinmetz ..1l4/16.11 X 1,420,254 6/1922 Hammond ..343/700 X 2,801,411 7/1957 Weinstock ..343/18 51 Oct. 17,1972

2,401,583 6/1946 Redfield et a1. ..114/15 2,331,735 10/1943 Schwab ..114/240 1,296,226 3/1919 Stow ..1 14/15 636,382 11/1899 Hamel ..114/15 FOREIGN PATENTS OR APPLICATIONS 957,858 2/1957 Germany ..343/18 Primary Examiner-Benjamin A. Borchelt Assistant Examiner-Thomas B. Webb Attorney R. S. Sciascia 0. Watson EXEMPLARY CLAIM 1. in combination with a submarine having a hull, a snorkel housing extending vertically from said hull, a water nozzle having a horizontal flow axis fixedly secured to said snorkel, means connected to said nozzle for admitting water thereto, and adjusting means for controlling the amount of water and shape of water spray released from said nozzle, whereby the amount of radar echo from said exposed submarine is effectively diminished and detection of said submarine is obviated.

3 Claims, 5 Drawing Figures PATENTED 0B1 17 I972 SHEET 1 [IF 2 FIG. I

FIG. 4

FIG. 5

INVENTOR W H YMOW/ T Z EM/L ATTORNEY PATENTEDum n ma SHEET 2 0F 2 4 w 2 W m\\\-; U 1

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INVENT OR EM/L m Hmow/rz ATTORNEY SUBMARINE SNORKEL CAMOUFLAGE METHOD The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

The present invention relates to a protective system for submarines and more particularly to a water nozzle attachment, secured to the snorkel breathing valve, for

' produced by a travelling snorkel tube.

Heretofore, there has not been available a means to protect submarines from radar detection and conceal the wake of the submarine by the use of a curtain of water. Prior to the use of this invention, it has been necessary to float wave shields or deflectors upon the water for interference purposes and 'said shields were not adaptable for use with a moving ship. Furthermore, the wake produced by a travelling snorkel tube was not concealed. Prior methods of snorkel camouflage utilize materials which are designed to be absorptive or nonreflective with respect to radar energy. In actual practice this type of material is not completely effective in shielding the snorkel from radar detection. The present invention fills the need to augment present methods of snorkel camouflage by deflecting radar waves and concealing the wake of the submarine simultaneously. The

' water curtain is opaque to microwave radar energy and effectively shields the snorkel as long as the fluid flow is continuous and non-turbulent. if the flow should become turbulent, it will still provide some measure of protection by first attenuating the radar energy and then masking any reflected snorkel signal with a sea clutter return from the turbulent curtain.

The amount of power returned to the radar from the sea at a given range is a function of the area illuminated by each pulse packet of energy at that range and by the size and number of scatterers (a function of sea state). The area illuminated by each pulse packet at a given range is approximately .4 VB (8c/2) where A area illuminated in square meters, V= range in meters, B horizontal beam width in radians, 8= pulse width in seconds and C velocity of light in meters per second. In a typical example of an airborne radar flown at 2,000 feet altitude utilizing a pulse width of 0.5 microseconds and a horizontal beamwidth of 2.0" the area illuminated at a range of 10 nautical miles is 48,600 square meters. By comparison, the area represented by a water curtain" l feet in diameter is A 1rr= 16.4 square meters. From the above, it is seen that the energy returned from the curtain" when the sea is rough enough to return detachable power to the radar set is not more than to 10" times that returned from the area illuminated and would be indistinguishable from the received sea clutter.

Assuming that the sea is perfectly smooth reflecting surface, a small amount of energy may be returned from the "water curtain" depending on the grazing angle of the incident energy at the angle at which the curtain" intersects the sea. This amount of energy may be so small as to be undetectable. However, this possibility can be obviated by maintaining nozzle pressure sufficient to project the curtain to a diameter such that the angle of intersection made with the sea is small.

An object of the present invention is the provision of a device for concealing the position of a submarine.

Another object of the invention is to provide a water nozzle attachment secured to a submarine to prevent detection by radar.

A further object of the invention is the provision of an attachment to conceal the wake produced by the snorkel tube of a submarine.

A final object of the invention is to provide various water spray patterns in accordance with the condition of the surrounding sea.

Other objects and advantages of the invention will become apparent to those skilled in the art as the disclosure is made in the following detailed description of a preferred embodiment of the invention as illustrated in the annexed drawing in which:

FIG. 1 shows a side elevation of a water nozzle attachment affixed to the snorkel tube of a submarine;

FIG. 2 illustrates an enlarged detail of the invention;

FIG. 3 shows a modification of the nozzle;

FIG. 4 illustrates a cutaway section of the embodiment of FIG. 3; and

FIG. 5 shows another modification of the nozzle attachment.

Referring now to the drawings, wherein like reference characters designate like or corresponding parts throughout the several views, there is shown in FIG. 1 a submarine l0 submerged below sea level 11 and having a snorkel l2 affixed thereto. A portion of the snorkel housing is above sea level for the use of a periscope. Attached to the snorkel housing 12 are one or more water nozzles 13 emitting a curtain of water 14. For a nozzle having a horizontal flow axis, the shape of the water curtain" is a parabolic cone. The final configuration of the curtain would depend on the height of the snorkel, the sea state, wind velocity, submarine velocity and water pressure. As shown in FIG. 1, the snorkel water curtain nozzle 13 is mounted atop the snorkel l2 and the water flow pattern 14 is omni-directional in the horizontal plane.

The water nozzle attachment 13 is shown in greater detail in F IG. 2 where a pipe inlet 19 delivers water to a variable delivery pump 20. The pump forces fluid through a pipe 21 to a main duct 22. The duct 22 is located within the snorkel housing 23, and has a circular, outwardly flared lip 28 formed on its top portion. Within the lowermost portion of said duct, a cam 24 is positioned by means of a shaft 25 and handle 26. As indicating pointer 27 is located on the handle 26 for a purpose hereinafter described. Located at intermediate points and transverse to the longitudinal axis of the duct 22 are supports 30 having a plurality of apertures 31 therein to permit the passage of fluid and also to slidably position a shaft 32 in longitudinal alignment. A cap 33 in the form of a disc is formed integrally with the shaft and is adapted to rest on the lips 28 of duct 22 when not in use. The cap 33 and lip 28 thereby form a throat opening 34.

Operation of the water nozzle attachment is as follows:

A source of fluid enters pipe inlet 19 and flows to the variable delivery pump 20. From the pump 20, the fluid is thereby forced by pressure through pipe 21 into the vertical duct or pipe 22, the latter being secured within the snorkel housing 23. The fluid, as indicated by arrows, is forced upwardly into duct 22 and through the throat opening 34 of the nozzle 13 and thereby forms a curtain of fluid 14.

By rotating the handle 26, the shaft 25, mounted within duct 22, turns the cam 24. The cam 24 thus actuates the vertical shaft 32 and causes the cap 33 of the nozzle to vary the throat opening 34 inorder to create variations of curtain diameters. The pointer 27 indicates various widths of throat openings. Thus, the adjustment of the amount of fluid delivered through the pump and the variation of the throat opening permit the adjustment of water curtain diameter and fluid density.

FIGS. 3 and 4 illustrate a modification of the nozzle described above. The nozzle 40 produces a similar omni-directional spray but utilizes a fixed throat opening 41 instead of a variable opening. About the circumference of the nozzle is a circular plate 42 having a plurality of apertures 43 therein which permit the fluid coming through the duct 22 to exit and form a spray. As shown more clearly in FIG. 4, the passageway is formed divergently as at 44 so as to eliminate turbulence.

FIG. shows an additional modification of a spraying means for concealing the snorkel 12 of the submarine from searching radar. A plurality of nozzles 50 are affixed to the snorkel housing 12 to emit a broad conical spray therefrom. Each of the nozzles 50 emits the fluid in a broad conical spray and each of said sprays intersect with adjacent sprays so as to provide a 360 circular spray of protection for the submarine. It is to be understood that such nozzles may be mounted in various positions and at various heights on the snorkel and at such attitudes to produce any desired pattern.

It is thus seen that the water curtain produced by the nozzle attached to the snorkel tube of a submarine acts effectively to protect the submarine from radar detection and also acts to conceal the wake produced by the moving snorkel tube.

Obviously many modifications and variations of the present invention are possible in the light of the above teachings. It is therefore to be understood, that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described.

What is claimed is: V

1. In combination with a submarine having a hull, a snorkel housing extending vertically from said hull, a water nozzle having a horizontal flow axis fixedly secured to said snorkel, means connected to said nozzle for admitting water thereto, and adjusting means for controlling the amount of water and shape of water spray released from said nozzle, whereby the amount of radar echo from said exposed submarine is effectively diminished and detection of said submarine is obviated.

2. In combination with a submarine having a hull, a snorkel housing extending vertically from said hull, a water nozzle having a horizontal flow axis fixedly secured to said snorkel housing, said nozzle having a water inlet, a vertical duct having an inwardly flared lip and mounted within said snorkel housing, cam means mounted within said duct, means for rotating said cam,

a v rtic l shaft concent 'call located within said duct and rest i ng on the irregu ar edge of said cam, said shaft having a disc integrally formed at its uppermost portion, said disc conforming to the size and shape of the outwardly flared lip of said duct, said disc and out wardly flared lip forming a throat portion therebetween; whereby rotation of said cam adjusts said shaft and disc to regulate the width of said throat portion and thereby emit an omni-directional spray or any other geometrical shape of water spray desired.

3. The apparatus of claim 2, said water inlet pipe in cluding a variable discharge pump to control the amount of water discharged through said throat portion.

* i ll t 

1. In combination with a submarine having a hull, a snorkel housing extending vertically from said hull, a water nozzle having a horizontal flow axis fixedly secured to said snorkel, means connected to said nozzle for admitting water thereto, and adjusting means for controlling the amount of water and shape of water spray released from said nozzle, whereby the amount of radar echo from said exposed submarine is effectively diminished and detection of said submarine is obviated.
 2. In combination with a submarine having a hull, a snorkel housing extending vertically from said hull, a water nozzle having a horizontal flow axis fixedly secured to said snorkel housing, said nozzle having a water inlet, a vertical duct having an inwardly flared lip and mounted within said snorkel housing, cam means mounted within said duct, means for rotating said cam, a vertical shaft concentrically located within said duct and resting on the irregular edge of said cam, said shaft having a disc integrally formed at its uppermost portion, said disc conforming to the size and shape of the outwardly flared lip of said duct, said disc and outwardly flared lip forming a throat portion therebetween; whereby rotation of said cam adjusts said shaft and disc to regulate the width of saId throat portion and thereby emit an omni-directional spray or any other geometrical shape of water spray desired.
 3. The apparatus of claim 2, said water inlet pipe including a variable discharge pump to control the amount of water discharged through said throat portion. 